Method of constructing foamed in place building containing heating wire

ABSTRACT

The invention is directed to a method of constructing a shelter and includes securing an inflatable form to a base element, inflating the form, applying a releasing agent to the form, positioning heating wires over the form, spraying polyurethane foam over the form, removing the form after curing said foam and then positioning a door and windows in the structure. The sprayed polyurethane foam may include an inner layer of noninterconnected cells and an outer layer of interconnected cells which permits a cooling effect when moisture is deposited on the structure.

United States Patent Mackie [54] METHOD OF CONSTRUCTING FOAMED IN PLACEBUILDING CONTAINING HEATING WIRE [72] Inventor: William L. Mackie,Ventura, Calif.

[73] Assignee: The United States of America as represented by theSecretary of the Navy [22] Filed: Dec. 29, 1969 [21] Appl. No.: 888,552

Related U.S. Application Data [62] Division of Ser. No. 762,463, Sept.25, 1968, Pat. No. 3,503,l67.

52 us. (21.; ..264/46, 18/5 P, 52/2, 264/32, 264/45, 264/272 5 1 Int. Cl..B29d 27 04 58 Field of Search ..264/46, 55, 32, 272, 45, 314; 52 309;18/5 P [56] References Cited UNITED STATES PATENTS 2,391,432 12/1945Marschner ..264/272X 2,878,153 3/1959 l-lacklander ..264/46X [451 June6,1972

2,928,138 3/1960 Boggs ..264/272 X 3,184,210 5/1965 Fassnacht. ..52/309X 3,200,236 8/1965 Geyer 52/173 X 3,277,216 10/1966 Turner........264/45 3,315,424 4/1967 Smith ..52/206 FOREIGN PATENTS ORAPPLICATIONS 586,508 11/1959 Canada ..264/46 Primary Examiner-JuliusFrome Assistant Examiner-Paul A. Leipold Att0meyRichard S. Sciascia, Q.Baxter Warner and Gayward N. Mann [57] ABSTRACT 3 Claims, 5 DrawingFigures PATENTEDJUH 6 I972 3.668.128!

'W/LL/AM L. MACK/E INVENTOR.

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ATTORNE Y5 CROSS-REFERENCES TO RELATED APPLICATIONS This application isa division of application serial No. 762,463 filed Sept. 25, 1968 nowU.S. Pat. No. 3,503,167.

STATEMENT OF GOVERNMENT INTEREST The invention described herein may bemanufactured and used by or for the Government of the United States ofAmerica for governmental purposes without the payment of any royaltiesthereon or therefor.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates generally to improvements in building construction andmore specifically to the fabrication of expendable lightweight sheltersfor quick erection in remote areas.

2. Description of the Prior Art Explorations are being carried out allover the globe and in many cases at remote regions with no facilitiesfor extensive logistic support. Such projects frequently require theprovision of suitable shelters to house both men and equipment for anextended period of time. The transportation of conventional buildingmaterials or prefabricated structures to such area is always difficultand frequently is impossible. It is, therefore an absolute necessity tohave materials that are lightweight and compact and which may readily beerected on site.

Many prior constructions employing foamed plastic materials forfabrication purposes have been proposed due to their low bulk andexcellent protective characteristics. However prior shelters wereprimarily of the prefabricated type wherein structural panels wereshipped to the site and assembled. An inherent disadvantage of suchpractices includes damage to panels during transit and water leakage atthe joints of assembled panels in inclement weather. In few instances,unit moles have been shipped to the site and processed in the field butthis did not satisfy the necessary requirements of low bulk and weight.

SUMMARY OF THE INVENTION The present foam plastic shelter is built towithstand polar, tropic, desert and other harsh environments andincludes an inflatable form which is unfolded at the site and inflatedwith a suitable air compresser. A layer of plastic foam is sprayed overthe form and after curing the mold or form may be deflated and removed.

Prefabricated window frames, doors and vents may be manufactured withsimple hand tools and then placed in the shelter or alternatively theframe elements thereof may be properly positioned in the shelter andfoam sprayed thereon. Plywood or foam plastic which is pressed into asmooth footing may be used for the floor. Plumbing, ductwork andelectric wiring may be laid across the form uninsulated and will beanchored in place by sprayed foam plastic which also acts to insulatethe pipes, ducts and wires.

STATEMENT OF THE OBJECTS OF INVENTION An object of this invention is toprovide a simple, strong and effective lightweight shelter for men andequipment in remote or harsh environments capable of being easilytransported and which can be erected in a minimum time in the field.

Another object is to provide an improved shelter made of foamed plasticmaterial sprayed over a collapsible form.

Still another object is to provide such a shelter having improvedthermal characteristics.

Other objects, advantages, and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION or THE DRAWING FIG. 1 is a side elevational view of aninflatable form used in the construction of this invention, shown fullyinflated.

FIG. 2 is a side elevational view with a portion of the plastic coveringbroken away of the inflated form upon which foam plastic has beensprayed.

FIG. 3 is an enlarged cross section of a portion of the plastic shelterwall showing the inner monocellular layers of plastic foam and outerinterconnected cell layer of foam.

FIG. 4 is a side elevation of a finished shelter with door, window andvent in place.

FIG. 5 is an enlarged cross sectional view of an embodiment having afiberglass mat incorporated into the finished shelter.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings indetail there is shown an inflatable form 10 in erect or inflatedcondition. The form is constructed of a flexible material such asadhesively bonded nylon fabric that can be folded into a compact packagewhen not in use and may be shaped to any desired configuration.

Form 10 may be positioned on any suitable base 12 such as a plywood diskor platform and may be inflated by a pressure means connected to thehose l4. The pressure within the form must be sufficiently great towithstand the weight of any additional substances which may be appliedto the form surface. A conventional mold or form releasing agent may besprayed over the form surface prior to application of the foam plasticcasting material to facilitate the form removal once the cast materialhas cured.

After suitably inflating the form 10 and application of the releasingagent, a casting material 18 such as a foam plastic is sprayed over theform surface to a sufficient depth and allowed to cure. While thecasting material may be any suitable substance, it is preferably apolyurethane due to its excellent nonflammable and insulationcharacteristics. After the plastic urethane foam casting material hascured, the form is collapsed and removed from the cast shelter.

For use in hot, dry climates the sprayed plastic urethane foampreferably includes a waterproof insulating inner monocellular layer ofnon-interconnected cells 20 and an outer porous layer interconnectedcells 22 (see FIG. 3). With this construction moisture deposited uponsuch a structure and allowed to filter down the outside wall willproduce a pronounced cooling effect by evaporation.

If desired a metallized urethane foam may be employed to improvestrength and control heat transmission when the shelter is located in anintemperate climate.

An impregnated fiberglass mat 24 may optionally be placed over theinflated form 10 prior to application of the foamed urethane castingmaterial 20. The mat becomes in inherent part of the finished shelterand serves as a vapor barrier against rain or snow. Note FIG. 5.

In order to provide heating in the shelter suitable conductors 26 suchas nicrome wires may be wound on the form and anchored in place by thesprayed foam urethane casting material 20. When the foam has cured andthe inflatable form removed from the shelter, the embedded wires remainattached to the inside surface of the shelter. Upon addition of asuitable power source not shown in the drawing, the conducting wires 26may be connected thereto for adequate heating of the shelter. Theurethane foam is an excellent electric insulator and inhibits anyelectrical short circuits in the heating wires.

Door, window and vent openings may be cut out of the cast urethanematerial 20 and prefabricated doors 28, window frames 30 and vents 32may be inserted in the openings. Conversely the doors 28, window frames30 and vents 32 may be attached to the inflated form 10 and then lockedin place with the sprayed foam plastic 20. After application of the foamto the entire form, said form is then deflated and removed through thedoor 28. Plywood may be used for the floor or urethane foam can besprayed on the floor area and patted into shape prior to curing.

The entire finished shelter is sufficiently light and compact to beairlifted by a helicopter to a desired location. Furthermore they may bemade in a number of sizes and configurations. It is emphasized that thesame form is easily removed from a completed shelter and reused ifadditional shelters are required.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

1. A method of constructing an expandable waterproof shelter comprising:

securing an inflatable form to a base element;

inflating said form;

applying a suitable releasing agent to said inflated form;

positioning heating wire over said inflated form;

spraying a polyurethane foam material over said form and said heatingwire;

curing said foam for a suitable period of time;

removing the form from said cast foam and;

positioning a door in said preshaped shelter.

2. The method as recited in claim 1 including the steps of attaching afloor to the bottom portion of said cast shelter and positioning windowstherein.

3. in the art of constructing a waterproof shelter by applying to aninflated form a coating of plastic polyurethane foam material which iscapable of hardening into a rigid structure independent of support bysaid form, the improvement which comprises the steps of:

applying said polyurethane plastic coating to said form as a series oflayers the innermost of which is waterproof and of the monocellular typemade up mainly of non-interconnected cells and the outermost of which isporous and made up mainly of interconnected cells constituting in effecta plurality of intercommunicating voids;

the said innermost layer of said coating being characterized by itsexceptional heat and moisture resistant qualities, and the saidoutermost layer by its porosity and ability to retain moisture incidentthereon so as to provide an evaporative cooling effect for the wall ofsaid shelter.

2. The method as recited in claim 1 including the steps of attaching afloor to the bottom portion of said cast shelter and positioning windowstherein.
 3. In the art of constructing a waterproof shelter by applyingto an inflated form a coating of plastic polyurethane foam materialwhich is capable of hardening into a rigid structure independent ofsupport by said form, the improvement which comprises the steps of:applying said polyurethane plastic coating to said form as a series oflayers the innermost of which is waterproof and of the monocellular typemade up mainly of non-interconnected cells and the outermost of which isporous and made up mainly of interconnected cells constituting in effecta plurality of intercommunicating voids; the said innermost layer ofsaid coating being characterized by its exceptional heat and moistureresistant qualities, and the said outermost layer by its porosity andability to retain moisture incident thereon so as to provide anevaporative cooling effect for the wall of said shelter.